The problem of constructing smooth and durable grade crossings where highways and railroads intersect has been a difficult one to solve on a long term basis. Modern structures normally provide reinforced concrete panels which can either be prefabricated or constructed in place. Because of the normal flexibility of the rails which deflect as a train passes over them, it has not been easy to design such a crossing to provide such flexibility and yet provide the normal rigidity required of a highway surface. Most of the modern structures are directed to the prefabricated panels which are joined in some fashion to the running railroad rails so as to be deflected along with the rails when the train passes over and to remain relatively rigid when automobiles are crossing in the other direction. Typical of the modern devices are those shown in U.S. Pat. Nos. 3,341,123 to Holthausen; 3,863,840 to Szarka et al; and 3,955,761 to Szarka et al. The constructions of the prior art employ special clips or bridging members that can be bolted to the tie supporting the main rail and thereby rigidly attach the prefabricated panel to the rail and its supporting tie so that the entire combination will move and flex together. This is now believed to be an undesirable feature if the proper type of crossties and their associated structures are employed. Another disadvantage of some of these prior art structures is that the panels are positioned as closely as possible to the running rails so as to provide a smooth surface for the automobile crossing, but in so doing open spaces are often left on each side of the rail which may catch foreign objects passing over the crossing and collect dirt and trash that cannot be easily removed.
It is an object of the present invention to provide an improved grade crossing structure that is uncomplicated by clips and bridge members joining the panels to the rails and which leaves no open spaces except that which is necessary for the flanges on the wheels of the railroad cars.
A railroad grade crossing where a highway intersects a pair of parallel railroad rails supported by and affixed to a plurality of substantially rigid and non-compressible parallel ties, the associated structure of generally rectangular shape having two sides interfacing with the highway and two ends intersected by the rails, the structure including a plurality of interior panels between the pair of rails and a pair of pluralities of exterior panels joining the outside of each rail to the highway, each of the interior and exterior panels being generally in the shape of a right rectangular prism having an upper rectangular surface, a lower rectangular surface, and four rectangular sides, each panel constructed of four railroad rail sections forming the sides of the panel and being positioned with the base of the rail section in the upper surface of the panel, the four rail sections being joined with sufficient reinforcing metal cross pieces to produce a rigid structure with all the remaining space between the upper and lower surfaces of the panel interiorly of the four rail sections filled with structural concrete, and with all exterior irregularities, including the exterior portions around the four rail sections, filled with an elastomeric compound; each interior panel having on its lower surface in the vicinity of each corner a guideway opening through the lower surface and terminating spacedly downwardly from the upper surface and cooperating with respective and spaced studs firmly attached to and upwardly projecting from the parallel ties underlying the guideways, each exterior panel having on its lower surface at least a pair of guideways opening through the lower surface and terminating spacedly downwardly from the upper surface, at least a pair of studs firmly attached to and upwardly projecting from respective and spaced parallel ties underlying the pair of guideways; and each panel being substantially completely supported on a plurality of parallel ties and separated therefrom by a layer of an elastomeric compound, the studs in the guideways of the interior and exterior panels permitting limited lateral and vertical relative movement between the ties and panels with the layer of elastomeric compound dampening the vibrational relative movement therebetween; the upper surface of the interior panels and the exterior panels at the ends of the associated structure sloping downwardly from a location adjacent the shoulders of the highway to a juncture with the lower surface.